ecudoctors.com - Anyone Have Experience With
01-12-2015, 09:39 AM
#16
I don't know exactly what the differences are with these two DME's. But let's not confuse OBD 1 and OBD 2 with the actual electronics that are part of the DME. The OBD system that Porsche has designed is contained in a separate module (i.e. another physical box) that deals exclusively with the OBD 1 or OBD 2 emissions values which are measured as required by the DOT. The DME itself merely "talks" to the OBD to make sure all the emissions parameters are measured and within limits or it throws a code. There is more feedback data that the OBD 2 system has over the OBD 1 for the 993 in that it now uses 4 oxygen sensors (two pre-cat and two post-cat) to determine how well fuel has been burned. This may play a role in making a more sophisticated system to control how an engine can better idle or respond to air/fuel changes.
So its a separate module, eh? Do you happen to know where this module is located?
However, what I am primarily referring to regarding the LWF and idling issues are the DME functions that are responsible for engine management which includes monitoring and feedback for such as fuel trim, timing, fuel detonation (or "knock sensors"), mass air flow readings, ignition timing, fuel timing (on off times, duration), flywheel RPM's, etc. I've just been told from more than one Porsche mechanic that when Porsche made the newer ('96 and later) DME's, they were better designed to deal with the LWF rpm issues. Not sure if it's due to a faster processing, newer widened parameters, the additional oxygen sensors pre and post cat, or something else.
I am sure Steve Weiner has all the answers as to why this is.
By the way ... I really enjoy all this conversation we are having here. It helps to learn and understand all the engineering design that went into building our 993's that are now almost 20 years old and were way ahead of their time in terms of performance!
I am sure Steve Weiner has all the answers as to why this is.
By the way ... I really enjoy all this conversation we are having here. It helps to learn and understand all the engineering design that went into building our 993's that are now almost 20 years old and were way ahead of their time in terms of performance!
01-12-2015, 01:00 PM
#17
Rennlist Member
But what I was trying to distinguish between are the more intimate variables related to the ECU (or DME) from the OBD parameters. The DME system receives up to 1,000 separate items of data input per second, including engine speed, air intake volume, air temperature and density, throttle position, accelerator position and vehicle speed. The data is then evaluated by a microprocessor and translated into commands for the fuel injection and ignition systems. Whereas, the OBD "system" is standardized DOT requirement that really determine things that are reserved for more of the emissions of the car - such as cleanliness of fuel burning.
So I don't believe (experts chime in please) that simply migrating from an OBD 1 to an OBD 2 system is what makes the newer DME more resilient to idle stalling issues, but I could be wrong. I think it has more to do with the newer technology (a better processing of data perhaps) that is incorporated into the DME which has a better response to RPM changes measured by the flywheel.
Last edited by mgianzero; 01-12-2015 at 04:03 PM.
01-12-2015, 09:19 PM
#18
Rennlist Member
If stalling after LWFW I would adjust the ICV rather than reflash. Even with Protomotive tuning I had to tweak mine. Remove, clean it well and then break the seal off the adjusting screws. It took a little fiddling but now it's 100% perfect!
01-12-2015, 10:06 PM
#19
tempts in adjusting.I dont have any idle issues, so I am not willing to try to screw with a well functioning ICV just outta curiousity.
Marc,
Thank you for your description of how a 96 ECU may be more robust...Sounds like the difference between an 8088 computer; to the subsequent 286 machines.
01-12-2015, 10:45 PM
#20
Rennlist Member
Good point Paul. It might simply be the speed of the processor that makes them respond quicker. Again, I am not sure of the specific architecture of each of these DME's. But this does raise my curiosity a bit.
01-13-2015, 01:31 PM
#22
Intermediate
Thread Starter
Guys, I started this thread to question if anyone had experience with ecudoctors and amongst the excitement I started off mentioning I was getting ready to do a LWF conversion. I'm not concerned with the stalling issues as Steve W said if everything is operating properly an OBDII model won't have an issue. My goal was to see if anyone had had ecudoctors convert there ECM to a programable unit to gain a few extra horses?
My apologies for the confusion and thanks to the ones who responded.
Ben
My apologies for the confusion and thanks to the ones who responded.
Ben
01-14-2015, 11:41 AM
#23
Sorry, but I think I miss spoke when I said "physical box". It's not really a separate module for OBD, but rather a series of inputs that are monitored that talk to the ECU. That is why an OBD 2 on the 993 has an 88 pin interface, whereas the older OBD 1 has a 55 pin connector. My bad - I didn't mean to say a separate box. I was thinking about the immobilizer when I wrote that.
But what I was trying to distinguish between are the more intimate variables related to the ECU (or DME) from the OBD parameters. The DME system receives up to 1,000 separate items of data input per second, including engine speed, air intake volume, air temperature and density, throttle position, accelerator position and vehicle speed. The data is then evaluated by a microprocessor and translated into commands for the fuel injection and ignition systems. Whereas, the OBD "system" is standardized DOT requirement that really determine things that are reserved for more of the emissions of the car - such as cleanliness of fuel burning.
So I don't believe (experts chime in please) that simply migrating from an OBD 1 to an OBD 2 system is what makes the newer DME more resilient to idle stalling issues, but I could be wrong. I think it has more to do with the newer technology (a better processing of data perhaps) that is incorporated into the DME which has a better response to RPM changes measured by the flywheel.
But what I was trying to distinguish between are the more intimate variables related to the ECU (or DME) from the OBD parameters. The DME system receives up to 1,000 separate items of data input per second, including engine speed, air intake volume, air temperature and density, throttle position, accelerator position and vehicle speed. The data is then evaluated by a microprocessor and translated into commands for the fuel injection and ignition systems. Whereas, the OBD "system" is standardized DOT requirement that really determine things that are reserved for more of the emissions of the car - such as cleanliness of fuel burning.
So I don't believe (experts chime in please) that simply migrating from an OBD 1 to an OBD 2 system is what makes the newer DME more resilient to idle stalling issues, but I could be wrong. I think it has more to do with the newer technology (a better processing of data perhaps) that is incorporated into the DME which has a better response to RPM changes measured by the flywheel.
Second: the difference between OBD1 and OBD2 while great on the hardware side isn't so great on the software side
Comparing ony '97/98 RoW manuel vs '97/98 US manual trans
While OBD1 is 55pin only 47 pins are used, OBD2 is 88 pin but only uses 55pin
of the used pins 2 of the OBD1 are for varient coding to access different internal maps, these aren't use in OBD2, so there are a total of 10 used pin difference between the systems
of these to most are related to the Oxygen sensors, OBD1 uses 3 pins for 1 oxygen sensor, OBD2 uses 7pins for 4 Oxygen sensors
the remaining 3 pins are related to the SAI timing, AC and fuel level
01-14-2015, 01:23 PM
#24
Rennlist Member
Guys, I started this thread to question if anyone had experience with ecudoctors and amongst the excitement I started off mentioning I was getting ready to do a LWF conversion. I'm not concerned with the stalling issues as Steve W said if everything is operating properly an OBDII model won't have an issue. My goal was to see if anyone had had ecudoctors convert there ECM to a programable unit to gain a few extra horses?
Ben
Ben
I apologize for getting so far off topic that we seemed to lose site of your original question. My bad.
In following with the OP, would you then recommend ECU Doctor for this supposid "performance" enhancement, or are you merely recommending them if your ECU needs repair?
Second: the difference between OBD1 and OBD2 while great on the hardware side isn't so great on the software side
Comparing ony '97/98 RoW manuel vs '97/98 US manual trans
While OBD1 is 55pin only 47 pins are used, OBD2 is 88 pin but only uses 55pin
of the used pins 2 of the OBD1 are for varient coding to access different internal maps, these aren't use in OBD2, so there are a total of 10 used pin difference between the systems
of these to most are related to the Oxygen sensors, OBD1 uses 3 pins for 1 oxygen sensor, OBD2 uses 7pins for 4 Oxygen sensors
the remaining 3 pins are related to the SAI timing, AC and fuel level
Comparing ony '97/98 RoW manuel vs '97/98 US manual trans
While OBD1 is 55pin only 47 pins are used, OBD2 is 88 pin but only uses 55pin
of the used pins 2 of the OBD1 are for varient coding to access different internal maps, these aren't use in OBD2, so there are a total of 10 used pin difference between the systems
of these to most are related to the Oxygen sensors, OBD1 uses 3 pins for 1 oxygen sensor, OBD2 uses 7pins for 4 Oxygen sensors
the remaining 3 pins are related to the SAI timing, AC and fuel level
So are you implying that the '96 and newer ECU is better for idling issues because of better processing power, or improvements in the algorithms measured and response to changes in rpms? Or are you saying that there is really no difference except for OBD monitoring which has little to no effect on engine performance or idling issues?
01-15-2015, 10:29 AM
#25
Bill,
In following with the OP, would you then recommend ECU Doctor for this supposid "performance" enhancement, or are you merely recommending them if your ECU needs repair?
In following with the OP, would you then recommend ECU Doctor for this supposid "performance" enhancement, or are you merely recommending them if your ECU needs repair?
Bill,
So are you implying that the '96 and newer ECU is better for idling issues because of better processing power, or improvements in the algorithms measured and response to changes in rpms? Or are you saying that there is really no difference except for OBD monitoring which has little to no effect on engine performance or idling issues?
So are you implying that the '96 and newer ECU is better for idling issues because of better processing power, or improvements in the algorithms measured and response to changes in rpms? Or are you saying that there is really no difference except for OBD monitoring which has little to no effect on engine performance or idling issues?
I have a '95 OBD19US) and a '97 OBD1(RoW), both have lw flywheels, the idle on the '95 was low in one chassis and would occasionally stall when the AC was in use and fine in w/ higher idel and no stall in another chassis, I can only assume that chassis 1 had a vacuum leak that caused the low idle. The '97 Has a custom chip that I specified a 900rpm idle on to accommodate the cams. I had tried adjusting the idle by modifying the ICV, this was only a temporary fix as the idle soon returned to it's previous value under the control of the ECU, this chassis also had a power robbing vacuum leak that affected the vram and resonance flap operation but not the idle.
again I don't know the specifics but Porsche showed a reluctance to change a lot of things except the hardware when they changed from Motronic 2.1 to Motronic 5.2 on the OBD2 cars